(a) Field of the Invention
The present invention relates to a method and apparatus for measuring oil aeration of an engine. More particularly, the present invention relates to a method and apparatus for measuring oil aeration of a test engine useful for establishing a minimum oil level while designing an engine.
(b) Description of the Related Art
Typically an engine produces a substantial amount of combustion heat and frictional heat during its operation. Therefore, an appropriate supply of oil and coolant must be provided for proper engine operation. For that purpose, an engine is provided with, in its cylinder block and its cylinder head, a lubrication system for oil supply including a hydraulic pump, oil galleries, and oil jets, and a cooling system for coolant supply including components such as a water pump and a water jacket.
The engine oil to be supplied to friction points and operating parts of the engine is stored in an oil pan mounted to the engine at its lower side. The oil stored in the oil pan is drawn by a hydraulic pump in accordance with the engine operation, and is then supplied to each part requiring lubrication through the oil galleries. In that way, the oil circulates through the engine, and it returns to the oil pan when the engine is turned off.
The oil may gradually be lost or degraded by burning in a combustion chamber or leaking out of the engine. Therefore, the amount and state of the engine oil contained in the engine should be periodically checked such that maintenance thereof may be applied when needed.
In an engine test room of a vehicle maker, a minimum oil level that may ensure optimal operation of the engine is established. In order to check the oil level, an engine is traditionally provided with an oil level gauge in the form of a dipstick. Recently, it has become possible to check the oil level electronically.
In order to establish an optimal value of the minimum oil level, oil aeration of a test engine has been measured, and the minimum oil level is established to a value such that the oil aeration might be sufficiently low to provide an oil level above the minimum oil level. However, it is typically required to take the oil from the test engine, and thus real time measurement of the oil aeration is not possible.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore, it may contain information that does not form the prior art that is already known in this country to a person or ordinary skill in the art.